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FP3 and Hyper-V GRT Failures - V-79-40960-38521

Rick_C
Level 3

I thought I might post this to (hopefully) save anybody else the headaches I've run into over the past MONTH!

I upgraded my BE server to Server 2012R2.  I had already been on BE 15 (FP2)  As I was stepping through everything I noticed that FP3 had been released.  So...I applied it.  Apparently I did not get a good install but I had no indication of this...except that most of my backups were now failing and I was getting a TON of ODBC access errors just starting the services and trying to do a catalog job.

Well...long story short...I did a complete re-install of BE 15.  Was scared to go back to FP3 but I finally did...this time it apparently applied OK. (I did a manual install...not via LveUpdate.)

Well...here's what I want to point out.  While I had been running FP2 it didn't seem to have an issue with the fact that several of my Hyper-V VMs still had dynamic disks.  (I had totally forgotten this...mainly because they have been running this way *and backing up* just fine now for over 2 years.)  FP3 apparently made some changes in the area of that "fast processing" feature and now it's picky.  Yes, I know it is documented...but that little tidbit is really buried deep in the new BEADMIN guide.  I didn't catch it until probably my 3rd read. (Shame on me.)

Anyway...the symptom is that a Hyper-V job will do just fine as long as it is handling the physical portion of the Hyper-V host.  When it hits the VM section, it fails with an error saying that it cannot mount the VHD or VHDX to process.  (Sorry, I don't have the screenshot of the error any longer.)  For each VM in the job you get Error V-79-40960-38521.  Please note...even if only a couple of your VMs may have dynamic disks, EVERY VM backup fails (for me, anyway).  I would see lot's of VSS-related errors and issues which totally diverted me away from logically troubleshooting this with the VM disks.

If you are having issues such as this after applying FP3...make sure that none of your VMs are using any dynamic disks!  It's an easy fix via the VM settings screen (after stopping the VM.)  Just do a disk EDIT and CONVERT your disk to FIXED, either VHD or VHDX.  Also note...using dynamic disks is now considered NOT a best practice.

Hopefully this will save someone else from wasting their time as I did!

 

1 REPLY 1

Rick_C
Level 3

I found the error...

ERROR.jpg